Laughter really may be good medicine

Watching a funny movie seems to be as good for the heart as running through the park. In an experiment with 20 healthy young adults, researchers found that participants' blood flow improved when they watched a movie that made them laugh. In fact, the circulation boost was similar to what's been seen with aerobic exercise. However, that doesn't mean laughing should take the place of running. Instead, an optimal scenario might be to watch a funny movie while jogging on a treadmill, Researchers from the University of Maryland Medical Center, USA, did a study, which involved healthy men and women who submitted to several non-invasive measurements of blood flow in the arm's brachial artery. Dilation in this artery is a good indicator of blood flow to and from the heart. The measurements were taken before and after participants watched clips from a comedy film and from a distressing film. On average, the researchers found, participants' blood vessel dilation was more than 50 percent better after the comedy than after the depressing film. A number of studies have linked negative emotions, such as major depression and chronic hostility, to poorer heart health. Exactly why laughing might give a jolt to the circulation isn't clear. It's possible that it counters the effects that stress hormones can have on blood vessel function. In addition, laughter may spur the body's production of nitric oxide, a chemical that helps dilate blood vessels. Researchers have speculated that persistent elevations in stress hormones may be involved. But far less is known about the cardiovascular effects of positive emotions.